It is known that resin-bonded wire tools or electrodeposited wire tools, in which super abrasive grains (abrasive grains composed of diamond or CBN (Cubic Boron Nitride) with high hardness) have been adhered to the outer peripheral face of a long thin object that serves as a core wire, can be used to cut hard and brittle materials such as silicon and sapphire. A problem with resin-bonded wire tools in which the super abrasive grains are adhered to the core wire with a synthetic resin is that they wear out more quickly and the super abrasive grains are more prone to falling out than with an electrodeposited wire tool. In contrast, although an electrodeposited wire tool in which the super abrasive grains are adhered to the core wire by electrodeposition is more resistant to wear than a resin-bonded wire tool, a problem is that the plating process of electrodepositing the abrasive grains takes a long time. Consequently, it has been proposed in recent years that coated abrasive grains, the surface of which is coated with a coating layer composed of nickel, titanium, copper, or another such metal, be used in such electrodeposited wire tools in order to increase the electrodeposition rate during the manufacture of the wire tool (see Japanese Laid-Open Patent Application 2003-340729).
However, in the manufacture of an electrodeposited wire tool featuring coated abrasive grains, a problem is that an excess amount of abrasive grains are electrodeposited to the core wire in the course of electrodepositing the super abrasive grains by immersing the core wire in a plating bath containing super abrasive grains. The excess electrodeposited abrasive grains tend to fall off, which wastes the abrasive grains and also shortens the life of the wire tool. Also, if some treatment is performed to remove the excess electrodeposited abrasive grains from the core wire, this ends up taking more time and driving up the cost, and therefore lowers the wire tool manufacturing efficiency.